CE6999 : Fluid Driven Fracturing of Rock Mass
Date10th May 2022
Time03:00 PM
Venue Google Meet
PAST EVENT
Details
The fluid-driven fracturing of the rock mass is a complex process. The deformation of saturated rock mass is a hydromechanically coupled process involving measurement of pore fluid pressure and the deformation of the rock skeleton. The pore fluid pressure and the deformation of the rock skeleton are coupled and they relate each other through the governing differential equations. Fracture behavior in such coupled medium with fluid pressure needs special attention to the fluid surface load and the traction separation laws. This seminar will review the existing work on fluid-driven fracturing and the critical theories pertaining to understand the process. The linear elastic fracture mechanics concepts together with cohesive zone models, are discussed. A review of various cohesive zone models are given here, and corresponding suitability for modeling of rock fracturing process is discussed. From different laboratory and field tests, it has been found that the subsurface rock behavior is time-dependent, especially if the rock is saturated. There are two reasons for this time dependence. One is due to fluid consolidation, and another is due to rock skeleton viscoelastic behavior; the finite element formulation takes care of the consolidation part. Time dependency due to the viscoelastic rock skeleton for modeling hydraulic fracturing is not well studied. This seminar will give a brief review of the viscoelastic constitutive models, which will be used while modeling. The most commonly adopted finite element formulation for a saturated rock mass is presented here. The rock mass here assumed to be tight with very low permeability and therefore, the flow inside the rock is ignored, and deformation and pore-pressure degrees of freedom are only considered. Various techniques adopted for the fluid flow simulation inside the fracture is also discussed. Different analytical closed-form solutions and their assumed fracture geometries are presented. Various existing finite element techniques for simulating fluid-driven fracturing are discussed briefly. A summary with gaps has been introduced towards the end.
Speakers
Mr. Subhadeep Sircar, Roll No.CE17D410
Civil Engineering